OBJECTIVES: The aim of this study was to assess the indirect costs associated with types 1 and 2 diabetes mellitus (DM) from the perspective of the Social Insurance Institution (ZUS) in Poland. METHODS: The estimates were based on data from the year 2012 concerning absence from work due to the illness (sick leave) the amount of short term disability, the sufferers of which claim rehabilitation benefit, and the amount of permanent (or long term) disability, the sufferers of which claim disability pension. Costs were presented in Polish zloty (PLN). RESULTS: Total indirect costs of DM types 1 and type 2 in the year 2012 in Poland were 59 013 912 PLN and 66 597 701 PLN, respectively. The highest component of indirect costs of DM type 1 was sick leave (61%). Long and short term disability costs constitute 28% and 11% of total indirect costs of DM type 1, respectively. A slightly different situation was reported in the case of type 2 diabetes: long term disability costs were only 1% of total indirect costs, and short term disability had a slightly larger part of indirect costs (less than 5%). The highest component of indirect costs of DM type 2 was sick leave (95%). One sick leave of a person with types 1 or 2 diabetes generated a cost of lost productivity equal to 1 771 PLN or 1 585 PLN, respectively.  The cost of  disability pension per one person was higher than rehabilitation benefit, and equalled 41 398 PLN compared with 17 249 PLN (the average value of one short and long term benefit payment was the same for both types of diabetes). CONCLUSIONS: DM in Poland generated high indirect costs. The main component was sick leave; rehabilitation benefit and disability pension generated much lower costs for Social Insurance Institution.